Budget turbo 4.8 van
08-10-2015, 09:47 PM
#1
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Budget turbo 4.8 van
This will not be a sexy build. Cheap and quick. I'm sure you will spot a number of "wrong" things.
First some background:
I rock crawl and dirt bike and live in the high rockies. I built a tear drop camper earlier this year. My crawler doubles as a tow rig. Loaded with dirt bikes and the tear drop the old Toyota 5vzfe, as much as I love it, doesn't cut it in the mountain highways. Especially on 37" tires towing a camper.
We live at 7000ft above sea level, and have to go over a 9,000ft pass quite often.
Rock crawling doesn't need much HP. I've never owned a V8, or an auto or a forced induction powered vehicle before.
Initially I was looking for a V8 pickup. But nothing decent near by, and then I had the idea that with a van, the dirt bike could live in it and free up some limited garage space.
I came across a '97 Chevy 3500 Express van nice and cheap. The high mileage 5.7 was disappointingly tired. Rather than dump money into that, I was thinking LM7 swap with turbo.
So not necessarily looking to go super fast.
Ability to overtake uphill with a load when necessary. Good fuel economy when empty.
I found a wrecking '04 Tahoe and seller would part with the all I needed for reasonable money.
Swapped that into the van, which I admit was a much bigger job that I anticipated. Everything on the van is tight and hard to get to.
I assumed the motor was the 5.3 but when I got HP tuners to do the segment swap for the van's existing 4L80e, I discovered it was actually a 4.8.
Turbo time definitely. I was only about $1500 all in at this point.
The missus was against a 3rd vehicle of course, so politically this could not be a spendy project.
No off-the-shelf kit will fit an LS swapped van of course.
Consulted a friend and decided on a smaller turbo. Borg Warner S300SX3. Hoping for lower RPM spool than most guys.
The initial plan was to flip the manifolds and run the turbo up front. But that just won't fit in the van.
So plan B was rear mount. Ebay, scav pump, intercooler, BOV, wastegate. Custom to fit.
First some background:
I rock crawl and dirt bike and live in the high rockies. I built a tear drop camper earlier this year. My crawler doubles as a tow rig. Loaded with dirt bikes and the tear drop the old Toyota 5vzfe, as much as I love it, doesn't cut it in the mountain highways. Especially on 37" tires towing a camper.
We live at 7000ft above sea level, and have to go over a 9,000ft pass quite often.
Rock crawling doesn't need much HP. I've never owned a V8, or an auto or a forced induction powered vehicle before.
Initially I was looking for a V8 pickup. But nothing decent near by, and then I had the idea that with a van, the dirt bike could live in it and free up some limited garage space.
I came across a '97 Chevy 3500 Express van nice and cheap. The high mileage 5.7 was disappointingly tired. Rather than dump money into that, I was thinking LM7 swap with turbo.
So not necessarily looking to go super fast.
Ability to overtake uphill with a load when necessary. Good fuel economy when empty.
I found a wrecking '04 Tahoe and seller would part with the all I needed for reasonable money.
Swapped that into the van, which I admit was a much bigger job that I anticipated. Everything on the van is tight and hard to get to.
I assumed the motor was the 5.3 but when I got HP tuners to do the segment swap for the van's existing 4L80e, I discovered it was actually a 4.8.
Turbo time definitely. I was only about $1500 all in at this point.
The missus was against a 3rd vehicle of course, so politically this could not be a spendy project.
No off-the-shelf kit will fit an LS swapped van of course.
Consulted a friend and decided on a smaller turbo. Borg Warner S300SX3. Hoping for lower RPM spool than most guys.
The initial plan was to flip the manifolds and run the turbo up front. But that just won't fit in the van.
So plan B was rear mount. Ebay, scav pump, intercooler, BOV, wastegate. Custom to fit.
08-10-2015, 10:16 PM
#3
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This is pretty much the only config I could find to work for the turbo. Next to the trans. Only just fits between trans and frame. Not ideal to have exhaust turn sharply like that but the only option.
Couldn't even get a 90 degree bend to fit in there. Not great for pressure waves or flow rates.
TIGing up the charge pipe.
Charge pipe follows the frame rail.
08-10-2015, 10:41 PM
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More details:
- 04 Tahoe 4.8 remained completely stock
- 60 lb injectors
- ebay manifold referenced fuel pressure regulator
- S300SX3 66mm 0.88 a/r
- cxr 3" intercooler, BOV and charge pipe
- 44mm chinese wastegate - 10 psi spring
- ASPX wideband connected to A/C pressure signal
- tr6 plugs
- cut up stock exhaust
- thrush 3" muffler
- ebay scav pump
- walbro 400lph fuel pump
- hp tuners 2 bar os
~$1,900 in parts.
Verdict:
With the engine off my boost gauge reads -3 psi. i.e. 80kpa baro where I live.
My tune is still super conservative - rich and 10 degrees of timing.
The whole time I've had my dirt bike stashed in the back. Did the first propper trip on the weekend with 2 bikes in the back. Still open loop and tuning the VE table.
At 70% throttle, manifold pressure goes above ambient at ~2,000 rpm. At 3,500 rpm the map goes exponential and 5,000 rpm comes around pretty quickly.
Puttering around town it feels like a nice 4.8. Pretty tame. Low down torque is not going to snap anyone's neck in a 6,000lb van with 800 lbs of gear and people in it.
Head up a mountain pass at the speed limit you notice the extra - very little throttle to sit at the speed limit uphill. Notice it not having to kick down to hold speed.
Overtake traffic going up hill and open the throttle - it gets angry - kicks down, very little lag before boost and a lot of response.
Frankly it's amazing to be able to overtake uphill at 70+ mph at ~9,000 ft elevation with a load.
Very happy at this point. Still want to do a dyno tune and see how much timing I can put back in.
My friends are excited to see who I can chop at the lights in a rusty old 6,000lb sleeper.
- 04 Tahoe 4.8 remained completely stock
- 60 lb injectors
- ebay manifold referenced fuel pressure regulator
- S300SX3 66mm 0.88 a/r
- cxr 3" intercooler, BOV and charge pipe
- 44mm chinese wastegate - 10 psi spring
- ASPX wideband connected to A/C pressure signal
- tr6 plugs
- cut up stock exhaust
- thrush 3" muffler
- ebay scav pump
- walbro 400lph fuel pump
- hp tuners 2 bar os
~$1,900 in parts.
Verdict:
With the engine off my boost gauge reads -3 psi. i.e. 80kpa baro where I live.
My tune is still super conservative - rich and 10 degrees of timing.
The whole time I've had my dirt bike stashed in the back. Did the first propper trip on the weekend with 2 bikes in the back. Still open loop and tuning the VE table.
At 70% throttle, manifold pressure goes above ambient at ~2,000 rpm. At 3,500 rpm the map goes exponential and 5,000 rpm comes around pretty quickly.
Puttering around town it feels like a nice 4.8. Pretty tame. Low down torque is not going to snap anyone's neck in a 6,000lb van with 800 lbs of gear and people in it.
Head up a mountain pass at the speed limit you notice the extra - very little throttle to sit at the speed limit uphill. Notice it not having to kick down to hold speed.
Overtake traffic going up hill and open the throttle - it gets angry - kicks down, very little lag before boost and a lot of response.
Frankly it's amazing to be able to overtake uphill at 70+ mph at ~9,000 ft elevation with a load.
Very happy at this point. Still want to do a dyno tune and see how much timing I can put back in.
My friends are excited to see who I can chop at the lights in a rusty old 6,000lb sleeper.
